The food of adult worker bees consists of pollen and nectar or honey. The nutritive value of pollen from different plants varies considerably (61, 72, 108, 117). Mixed pollens brought into the hives have a high nutritive value (115) and supply all the� necessary materials for proper development of young animals (4, 6, 68, 109). When dried, pollen quickly loses its nutritive value on storage at room temperature (42, 73, 112), therefore, in studying the nutritive value of pollen for bees, pollens of the same age, preferably freshly collected, should be used to preclude erroneous interpretations of results.